On iOS, I'm often considering using the mobile website of services instead of their app because of possible privacy concerns. Now I'm wondering if this is actually unnecessary.

So my question is: Which device or user data are apps able to collect without granting any explicit permissions?

Can they read my phone number, IMEI, can they see other installed apps etc.?

Let's assume it's a freshly installed app that I've never opened so far.

  • I’m tempted to close this as too broad since this seems more like a request for. Wikipedia article or off-site recommendation and I’m tempted to upvote since a clear explanation of when and how an app begins to send data might be useful even if the details change from release to release.
    – bmike
    Commented Jul 15, 2018 at 22:48
  • Perhaps edit the question to indicate which iOS major version? This post of mine gives some additional information on what apps can access in the service of device fingerprinting: security.stackexchange.com/questions/183698/…
    – pseudon
    Commented Jul 18, 2018 at 1:31
  • You may get have to elaborate in Ask Different Meta @FyodorGlebov the privacy tag needs many more good&great questions. This one is a little vague to my tastes - I’d like it to define user data so an objective answer would be forthcoming and it land on the “getting a lot of votes” page, personally
    – bmike
    Commented Jul 18, 2018 at 10:57

1 Answer 1


It might be simpler to approach this from the perspective of what info iOS developers must explicitly ask the user for permission. If it's not included in this list then the user must assume a developer can access that info without asking the user for permission.

As an iOS developer for a few years, I know that Apple locks-down almost all user info. I can access very generalized info such as the device you're using, model number, but I can't tie it to a specific person unless I ask your permission first.

My goal, and hope, is that others will [edit] and add to this answer as more info is found/discovered/released.

Source for the quote below is from Apple's developer docs.

Data protected by iOS system authorization settings includes location, contacts, calendar events, reminders, photos, media, and many other types as well.

That's pretty broad but it gives you an idea about what developers can't access without asking your permission first. Here's another list from that same document that indicates the data and resources protected by system authorization settings:

  • Bluetooth peripherals
  • Calendar data
  • Camera
  • Contacts
  • Health data
  • Health sharing
  • Health updating
  • Homekit
  • Location
  • Microphone
  • Motion
  • Music and media library
  • Photos
  • Reminders
  • Siri
  • Specht
  • TV provider

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